I use a bromine floater and also add 1 tbsp of brominating granules (85% sodium dichlor, 15% sodium bromide) after each use. (2 people for 15-20 minutes) Adding the granules after use was recommended by the vendor as well as another pool store to keep the bromine levels constant. So far it seems to be working. I have ordered a Taylor 2106 kit but haven't received it yet, which I plan to use to get an idea of my bromine demand. I don't trust the test strips. I have people coming over this weekend and want to know:
If 4 people use the spa for 15 minutes, do I add 4 tbsp of granules afterwards?
Should I put something in even before they get in?
Is there a calculation to figure out how much to put in (# people, amount of time in spa...etc)?
Also, can I put in MPS instead of the granules? I know one is an oxidizer and one is a disinfectant but I've heard different things.